Improvement in watch-case springs



B. P. CORBAN.

Improvement in Watch-Case Springs.

No.129,108, Patentedlulymmsm.

UNITED STATES PATENT CFFICE.

B. PERRY CORBAN, OF BRISTOL, ASSIGNOR TO ALLISON 4N. CLARK, OF PLAINVILLE, CONNECTICUT.

IMPROVEMENT IN WATCH-CASE SPRINGS.

Specication formin g part of Letters Patent No. 129,108, dated July 16, 1872.

To all whom it may concern.-

Be it known that I, B. PERRY CORBAN, of Bristol, in the county of Hartford and State 'of Connecticut, have invented a new and Irnproved Lift or Catch Spring for Watch-Cases, of which the following is a specification:

This invention consists of a new article of manufacture, to wit: A sheet-metal lift or catch spring, in which a wing formed at right angles to the body of the shank extends the whole length of said shank, and is swaged edgewise into circular form, as herein shown and described.

In the accompanying drawing, Figure lis a side eleva-tion of a watch-case litt-spring embodying my invention; Fig. 2, a transverse section of the same on line :v x; Fig. 3, a plan view of the blank from which said spring is made; and Fig. 4, a view of said blank as it appears after being subjected ,to the first set of swagingdies.

Sheetsteel of a suitable thickness is selected, and by means of a die and punch the springs are blanked out from said steel into the form shown in Fig. 3. This blank is then subjected to swaging-dies, which swage or bend the wing a of the shank A at about right angles to the body of said shank, and the win g or hook b is also curved into the usual and proper form. Another set of dies form the shank A and spring B into the desired circle or curvature, as shown in Fig. l. The screw-holes c are then drilled and threaded, after which the spring is hardened, tempered, and polished, when it is ready for the watchmaker or repairer.

When the spring is fitted to and secured within a watch-case it operates like any other spring for the same purpose. Ordinary springs for this purpose are forged from a solid bar of steel, and are, therefore, both heavy and expensive.

Watch-repairers, although they may have a large variety of styles and sizes of lift-springs on hand, nd always a still greater variety of styles and sizes of cases, so that considerable filing of the shank ot' the lift-spring is necesi sary in order to properly t a spring to a watchcase. The shank of the ordinary springs being solid and hardened, the iiling necessary to fit it is not only laborious, consuming much time, but also consumes or wears out les very rapidly, which is a considerable item of expense. This device may, if desired, be applied within a watch-case as a spring-catch.

My improved spring has the following peculiarities and advantages, viz.: It is much lighter than the ordinary spring. The thin edge of the metal forms the entire bottom and outer side ofthe shank, so that there is but a small amount of metal to beled in fitting the edge to the curvature of different-sized cases and to cases of different depths, thus saving largely over the ordinary spring the expense of tiles, time, and labor in fitting. The screwholes are made through the thin arm of the shank, and therefore can be diilled and threaded at much less expense and less breakage ot' tools than they can be in the ordinary solid shank.

The article consists of sheet' metal cut out and swaged, and can, therefore, be produced at a very small cost. Thus I not only produce a cheaper article, but one which is also better, more easily fitted, and obviates objections which have been made to the ordinary lift-springs now in common use. y

The exact form of the spring and the order of procedure described for forming it may be somewhat varied without departing from the main features of my invention.

I claim as my invention- As a new article of manufacture a sheet-metal lift or catch spring, in which the wing a, bent at a right angle to the shank A, extends the whole length of said shank, and is also swaged edgewise into circular form, as shown and described.

B. PERRY GORBAN. Witnesses JAMES SHEPARD, G. A. SHEPARD. 

